3D coronary artery imaging with phase reordering for improved scan efficiency

Abstract

Three‐dimensional (3D) coronary imaging has the potential to overcome problems resulting from vessel tortuosity and to reduce partial volume effects. With these techniques, however, acquisition times are long and respiratory motion artifacts problematical. This work describes the development of a method that applies phase encode reordering to 3D acquisitions, allowing larger navigator acceptance windows to be used, with a consequent reduction in acquisition time. This method is compared with navigator acceptance window methods (the acceptance‐rejection algorithm and the diminishing variance algorithm) and the retrospective respiratory gating technique, both in vitro and in vivo. The use of phase reordering with a 10 mm acceptance window provided a significant increase in scan efficiency over a non‐reordered 5 mm method (P < 0.001) with no significant change in image quality, and a significant increase in image quality compared with a non‐reordered image acquired in the same time (P < 0.05). A significant improvement in both image quality and scan efficiency was demonstrated over the retrospective respiratory gating method (P < 0.05). Magn Reson Med 41:555–562, 1999. © 1999 Wiley‐Liss, Inc.

Coronary MR Angiography: Current Status

“…These include retrospective gating, prospective gating, and prospective gating with slice-tracking [8,39,57]. Very sophisticated approaches to compensate for respiratory motion and improve scan efficiency, including the diminishing variance algorithm [49,50], phase reordering [25,26], and linear phase shift [17], have also been recently described.…”

Breath-Hold Three-dimensional Contrast-enhanced Coronary MR Angiography: Motion-matched k-Space Sampling for Reducing Cardiac Motion Effects

“…Careful investigations will be required to quantify and minimize them. This motion-matched k-space sampling technique can be regarded as a generalization of the respiratory-ordered phase-encoding method, which reduces motion effects by smoothing respiratory motion over the phaseencoding direction (39)(40)(41). This study provides new information on the concept of smooth motion distribution in k space (Fig 6): There are multiple view orders that can be used to smooth motion in k space, the degree of motion blurring varies with view orders, and an optimal view order may be identified to minimize motion blurring.…”

Coronary arteries

“…This has been shown experimentally by Jhooti et al [51] investigating several schemes to compensate prospective navigator data collection while analyzing the possible pitfalls of the retrospective navigator approach. The group concluded that image quality was in direct relation to the goodness of the acquired data during the central portion of k-space.…”

“…Other schemes are available to increase scanning efficiency even further. Jhooti et al [51] have proposed the use of centrically ordered acquisitions in which the central portion of k-space is collected with a small respiratory gating window (e. g., 1 mm) while the data for the outer portions of k-space are scanned with increasingly coarser gating windows (e. g., 3, 5, and 7 mm). This group claims that image quality is not harmed significantly with such procedure while scanning efficiency can be increased to 50 %.…”